93 ranger not starting

Here's the scenario, whenever i got the truck it ran great, and since then its had 2 cases where the motor completely dies during driving. first time i was able to wiggle some wires and it worked for a while longer. second time i replaced wires and plug and it ran fine for another week and a half. This time, i have replaced a fuel filter and now how 38 psi in my fuel rail, i have correct resistance in both sets of coil packs and injectors aslo get power to both from my battery. the engine will turn over, hit (once) hard enough to kick the starter out and die, and this only happens on occasion, not every time. any help would be appreciated

thanks for all the help but i think its a crankshaft position sensor.